HONOLULU, Hawaii (HawaiiNewsNow) - Activists are already planning to protest a proposed $1.5 billion high-powered radar on Oahu.

It’s a sensitive issue for the military which says it’s trying to improve Hawaii’s defense by protecting against ballistic missiles — while being environmental stewards.

There are three proposed sites for the radar. Two sites are at the U.S. Army’s Kahuku Training Area, and on Kuaokala Ridge at Kaena point, which is mostly State land adjacent to the U.S. Air Force Kaena Point Satellite Tracking Station.

The Missile Defense Agency says the project would be a flat facing radar, 80 to 90 ft. tall and about 50 feet wide. The site would be 50 to 80 acres with 100 acres for construction.

“There will be protests because people are already organizing around it,” said State Representative Amy Perruso (D-Wahiawa-Mililani Mauka).

She says once again, people are willing to be arrested.

"In the past, decades ago there has been really intense hostility between the military and the community and I don't want to go back to that situation, but the conversations that I'm a part of and that I hear, it's really troubling," she said.

Members of Malama Makua, who visited Kaena Point last month, say they oppose the radar because they’re against military proliferation and there’s a heiau in the proposed site called Mokaena, which the military says will be protected.

"There's a fenced in area that's considered a part of the main part of the heiau and for us it's like how do you know that," said Lynette Cruz, President of Malama Makua.

"Why would our ancestors want to set aside a portion of that area to be sacred. The whole thing is sacred," she added.

On Friday, military leaders at the state capitol stressed their commitment to environmental stewardship and not repeating mistakes of the past. They say there is no preferred site.

"What happens if both of these communities do not want this radar and we are down to the one site? At that point, that will all be packaged up. It'll all be sent through the proper channels to the Secretary of Defense, up to Congress," said Commander Richard "Scott" McGowen, assistant to the director to the U.S. Indo-Pacific Command at Missile Defense Agency.

“At that point, they will disseminate it and a decision will be made,” he added.

The Union of Concerned Scientists, an advocacy organization, doubts a radar could improve Hawaii's defense.

“These radars are meant to try to help you discriminate from the real target and a confusing decoy. We’ve never tested the system in anything like those conditions,” said Laura Grego, Union of Concerned Scientists, Senior Scientist in Global Security Program.

“I’m pretty skeptical that they would even work well,” she added.